Delta Update Product Feed Variants

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden. It makes the mutation nature clear (delta update) and specifies that only the listed attributes are affected for existing variants, and that no full re-upload is needed. It does not, however, disclose merge/overwrite semantics, partial-failure behavior, idempotency, or authorization requirements, which are meaningful gaps for a mutation tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single sentence front-loads the operation and scope and includes the key decision-relevant fact (no full catalog re-upload). There is no filler or repetition of schema field names beyond the meaningful summary.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Combined with the rich input schema, the description is sufficient to understand what to send: a feed_id and product/variant objects containing only changed fields. There are minor gaps such as no mention of what happens for unknown variant IDs or partial failures, but they do not block correct invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents feed_id, products, and the price/title/availability fields in detail. The description adds the concept of 'delta' (only changed fields) but does not explain field formats like minor-unit pricing; that is handled by the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a specific action (delta update), a clear resource (product feed variants), the updateable fields (prices, titles, stock availability), and the scope (existing variants in a linked merchant feed), distinguishing it from a full catalog re-upload. This is enough for an agent to select it without opening the schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The phrase 'existing variants ... without re-uploading the entire catalog' gives a clear usage context: partial updates to already-uploaded variant data. It implies that adding/removing variants or performing a full sync is out of scope, though it does not explicitly name a fallback tool or say 'do not use for new variants'.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.